Retrieves the version information which is stored in the manifest of a JAR

Version.scala

/**
 * Reads the version number out of the manifest.
 */
object Version {
  def apply: Option[String] = {
    val myClass = this.getClass
    val classFileName = s"${myClass.getSimpleName}.class"
    val myUrl = myClass.getResource(classFileName)
    val myUrlString = myUrl.toString
    val lastBang = myUrlString.lastIndexOf('!')
    myUrl.getProtocol match {
      case "jar" if lastBang > 0 =>
        val manifestPath = myUrlString.take(lastBang + 1) + "/META-INF/MANIFEST.MF"
        Some(new java.util.jar.Manifest(new URL(manifestPath).openStream()).getMainAttributes.getValue("Implementation-Version"))
      case _ =>
        None
    }
  }
}